Elevator control mechanism



Jan. 12, 1943. s. B. SANFORD 2,308,211

ELEVATOR CONTROL MECHANISM Filed April 20, 1942 4 Sheets-Sheet l Yl m mw W o N m 0 /T M w Q Ru QbQQ 0. n v' 6 m Q Q w m 4 M IHWUMU. R 7. 7. SW. mm CT. m m

Q E T w Fm 1& m E gm. m. m mu m AV" L T WNW E n H.. H M w u MN TP ,m L MN 0% H M fl R m C R m B T E 5D R W ADH -hw, R A /nMU w mm m m f v w I Iw m FIU .M W R m s w w Ell w mm m m & MN MW W M I m Jan. 12, 1943. s. B.SANFORD ELEVATOR CONTROL MECHANISM Filed April 20, 1942 4 Sheets-Sheet 29 u n 9 2 w N. Q g a 8 m E w o 0 on 8 m l m W .HLLJ R n w NW W "0 Q w Y/T 8 Q PS I E E. .l a E. 5 a n 2 8 S 3% R m N E V m S 6 E N R 0 w A Jan.12, 1943. s. B. SANFORD ELEVATOR CONTROL MECHANISM Filed April 20, 19424 Sheets-Sheet 4 IND LM 0A I I I I I I I I I I I I I I I I I o L i II T-ui mw fiI w IIIIIIIIIIIIIII Kv s w Rw III III III I KI QT IIIIIII I I II I III w IIIIIIIIIIIIIIII IIIIIIQIIIIIIIIIIIIIIIIIIIIIIDflMg ATTORNEYPatented Jan. 12, 1943 ELEVATOR CONTROL MECHANISM Selden BradleySanford, Yonkers, N. Y., assignor to Otis Elevator Company, New York, N.Y., a corporation of New Jersey Application April 20, 1942, Serial No.439,783

10 Claims.

operation of an elevator car so as to obtain accurate stops at thelandings.

There are various factors which afiect the accuracy of stopping of anelevator car. One or the principal factors is the load carried. by thecar. Assuming a constant retarding force, the car speed will be reducedto a given low speed in less distance when the elevator motor is liftinga heavy load than when it is lowering a heavy load. Various arrangementshave been provided for compensating for this effect. Among these areweighing devices carried by the car connected to register the loadsuspended on the hoisting ropes and arranged to utilize the measurementthus obtained to vary the point of initiation of 7 the stoppingoperation. The invention is directed to mechanism of this character.

The object of the invention is to provide an improved load weighingdevice carried by the elevator car for varying the distance for bringingthe car to a stop at a floor.

In carrying out the invention according to the arrangement which will bedescribed, resilient means is provided between the hoisting ropes and.the car framework. The load on the car is measured by the compression ofthe resilient means under different loads. The amount of thiscompression is amplified by lever mechaping operation. These cooperatingmeans are preferably in the form of an inductor switch carried by theend of the lever mechanism and inductor plates in the hatchway for thevarious landings. Mechanism is associated with the lever mechanism nearthe end thereof for holding the end of the lever mechanism in positionafter the load is measured to obviate any inaccuracies such as those dueto inertia or friction. The lever mechanism is made flexible to allowfor any strain during operation due to the end of the lever mechanismbeing held.

A general idea of the invention and the various features and advantagesthereof will be gained from the above statements. Other features andadvantages of the invention will be apparent from the followingdescription and appended claims.

In the drawings:

Figure 1 is a simplified schematic representa The present inventionrelates to controlling the vi tion of an elevator installation embodyingthe invention;

Figure 2 is a top view of a somewhat schematic representation of theload weighing device of Figure 1;

Figure 3 is a side view of the same with parts in section;

Figure 4 is a detail taken along the line 44 of Figure 3;

Figure 5 is a detail of resilient means employed between the ends of thehoisting ropes and the carframe;

Figure 6 is a simplified wiring diagram of an elevator control systemchosen to illustrate an application of the invention; and

Figure 6.9 is a key sheet for Figure 6 showing the electromagneticswitches in spindle form with the contacts and coils arranged on thespindles in horizontal alignment with the corresponding contacts andcoils in the wiring diagram.

The invention is of particular application to a slow speed elevatorinstallation, say of one hundred to one hundred and fifty feet perminute car speed, in which a polyphase alternating current motor isemployed to raise and lower the car. In such installations it is usualto slow down and stop the car simply by disconnecting supply of power tothe hoisting motor and applying the electromechanical brake. Inasmuch asthis provides the same retarding force for all loads, the

amount of coast of the car before it is brought to rest is greatest withfull load down and least with full load up. The load weighing deviceacts to provide accurate stops by initiating the slow down at distancesfrom the floor corresponding to the coast of the car for the particularload conditions and in view of its particular adaptability toinstallations of this nature and the relative simplicity of controlsystems for these installations, the invention will be described asapplied to an elevator system of this character.

For a general understanding of the invention,

7 reference may be had to Figure 1 wherein various parts of the systemchosen to illustrate the principles of the invention are indicated bylegend. The car is raised and lowered by means of the hoisting motorwhich drives a traction sheave over which pass the hoisting ropes forthe car and counterweight. An electromechanical brake is provided forstopping the'car and holding the car when at rest. The invention isillustrated as applied to a system in which the operation of the car iscontrolled by the passengers and intending passengers themselves bypressing hall buttons at the landings and car buttons in the tween locknuts 18 and the hitch plate.

car. These push buttons act through floor relays, these relays and theelectromagnetic control switches utilized in this system being arrangedon the control panel. In such systems mechanism actuated in accordancewith car movement is utilized. This mechanism is illustrated as in theform of a selector machine driven by a tape having teeth formed thereonfor actuating a sprocket driving wheel for the selector machine. Thetape is connected at one end to the top of the elevator car, passes overthe sprocket wheel and is connected at the otherend to thecounterweight. The selector machine comprises a crosshead which isdriven by a screw, which in turn is driven by the sprocket wheel to movethe crosshead in accordance with movement of the car. The crossheadcarries brushes for cooperating with stationary contacts to pick upcalls for the floors at which push buttons have been pressed. When acall is picked up this renders an inductor switch carried by the carefiective to initiate the stopping operation. Inductor plates areprovided in the hatchway for the various landings and, as the cararrives at a certain distance from the landing at which the call hasbeen picked up, the inductor switch moves into cooperation with theplate for that landing for the direction of car travel to initiate thestopping operation.

The distance of the car from the landing at which the inductorcooperates with the inductor plate is determined by the load weighingmechanism. The load weighing mechanism comprises a resilient connectionbetween the ends of the hoisting ropes and the car framework, the amountof compression of which is measured by a movable rod. The movement ofthis rod is amplified by a pair of levers pivoted on the car framework.The inductor switch is mounted on the outer end of the outer lever. Alocking device comprising a rack mounted on the outer lever adjacent theinductor switch and a magnetically actuated pawl mounted on the carframework in position to engage the rack to hold the inductor switch inposition corresponding'to the load carried by the car.

For a further discussion of the load weighing mechanism, reference maybe had to Figures 2, 3, 4 and 5. While these figures are still somewhatschematic, they are on a much larger scale and give a more comprehensiveidea of the operation of the mechanism. An installation having fourhoisting ropes is illustrated. Each hoisting rope It] is connected tothe car framework through a thimble rod II. A plate I2 is providedbeneath the top cross channels I3 of the car framework. This plate issecured to the cross channels by bolts l4. Below this plate is a hitchplate l5, the plate i2 being of the same size as the hitch plate. Arubber pad I6 is arranged between these plates. The thimble rods passthrough aligned apertures in the platesand rubber pad. Compressionsprings H are provided on the lower ends of the thimble' rods be- Thisarrangement is utilized to enable adjustment of the tension of theropes. Washers 20 are provided on each rod at each end of the spring.The apertures through the plates and rubber pad are made considerablylarger than the thimble rods 'to obviate any possibility of binding.

The upper washer 29 on each thimble rod is formed with a shoulder to fitinto the aperture in the hitch plate to maintain the thimble rod centralwithrespect to the aperture at this point.

The rubber pad is located with respect to the plates [2 and I5 by meansof pockets 2| in the pad into which the heads of bolts l4 and lugs 22 onplate l5 extend. The construction and properties of the pad are such asto support the car without undue transmission of vibrations thereto andto give a certain amount of overall compression when the load in the caris increased from nothing to full load. In this connection, holes 23 areprovided in the pad to provide a certain ratio of effective area tobulge area, with the effective area greater than the square of thethickness.

The pad is also provided with a central aperture 24 aligned with anaperture 25 in plate [2.

These apertures are for receiving a load measuring rod 26 which rests atits lower end on the top of hitch plate l5. As the load in the carincreases and compresses the pad, this rod is pushed upwardly withrespect to the car framework by the hitch plate 15. This provides amovement which is proportional to the change in load in the car. Thismovement is transmitted to the inductor switch by a system of le- Verswhereby amplification is obtained in an amount to provide the desiredrange of variation of slow down distances for the particularinstallation. This systemof levers comprises a lever 21 pivotallyconnected at one end to rod 26 and mounted on a fulcrum 28 secured toplate I 2. The outer end of lever 21 is connected by a link 30 to theinner end of a lever 3| mounted on a fulcrum 32 secured to the top ofchannels [3. The outer end of lever 3i is connected by a link 33 to theinner end of a lever 34. This latter lever is mounted on a fulcrum 35secured to the top of channels E3. The inductor switch 36 is mounted onthe outer end of lever 34. Levers 3| and 34 are amplifying levers, twolevers being utilized instead of one to increase the ampliflcationratio. Lever 21 is utilized to obtain the proper direction of movementof lever 34. A twenty-five to one amplification is readily obtained withthis lever system so that, with a pad which compresses one quarter inchfrom no load to full load, six and a quarter inches of movement of theinductor switch is provided which is suitable for an installation of2000 pounds at feet per minute.

Lever 33 comprises two offset arms [9 and 29 operably connected by across shaft 31, this arrangement being utilized to avoid the guides 39for the car. The arm [9 comprises two spaced members 38 and All toenable the link 33 to be adjustably connected thereto and thus permitadjustment of the lever ratio. This adjustable connection is provided byforming the link of two spaced members M and 42 and connecting the upperends of these members to a pin 43 slidable in slots 44 in the members 38and MB. A block 45 is arranged on the pin between members 38 and 40 andhas a threaded stud 43 secured thereto. This stud slidably extendsthrough an aperture in the yoke il connecting the inner ends of members33 and til. Adjusting nuts 48 on the stud are turned to shift the pin inthe slots to thereby change the lever ratio.

The inductor switch 36 is secured to the end of lever 34 by a bracket53; This switch may be of the construction shown in application of Lewiset al., Number 2,101,146 granted December 1'7, 1937. It comprises aframe 5| having two magnetizable plates 52 and 53 extending therefrombetween which is positioned an el'ectromag'net 54. The plates extendbeyond the magnet to form a pocket to receive the hatchway plates 55. Anarmature 56 is pivotally mounted on a bracket 51 secured to plate 52.When the plates 52 and 53 come opposite a hatchway plate underconditions where the electromagnet is energized, the armature is pulledinwardly against the force of a spring 58 into a slot in the end ofplate 52. When this takes place a movable contact carried by thearmature disengages thestationary contact on the frame to initiate thestopping operation, these contacts being designated 60. The hatchwayplates are secured to the hatchway wall by brackets 6|. iwo plates areprovided for each intermediate landing as indicated in Figure 1, thelower for initiating stopping of the car during up car travel and theupper for initiating stopping of the car when the car is travelling inthe down direction. These plates are positioned to provide accuratestopping of the car, preferably being set for the most prevailing loadconditions, which in many installations is two or three passengers.

The locking device for holding the inductor switch in load registeringposition comprises a segmental toothed rack 66 secured by a bracket 84to the outer end of lever 34 adjacent the inductor switch. This rack isadapted to be engaged by a pawl 65 actuated by an electromagnet 52arranged in a frame 63 mounted on a bracket 6'! secured to the top ofthe cross channels 3. This pawl 65 in the form of a bell crank ispivotally mounted on the frame 63. The pawl is biased by a spring 68into position disengaging the rack. The electromagnet is provided with aplunger E which is adapted to pull the pawl against the force of thespring into engagement with the rack. The electromagnet 62 is energizedto actuate the pawl into engagement with the rack after the load hasbeen weighed, thus locking the end of lever 34 and thus the inductorswitch in load registering position. The bracket 61 is formed with avertical slot 69 into which lever 34 extends to form a guide to insurethe proper positioning of the inductor switch with respect to theinductor plates.

A weight H is adjustably mounted on the outer end of lever 3| forbalancing the weight of the inductor switch and locking device carriedby the outer end of lever 34, the arms of the levers being chosen so asto place the system otherwise substantially in a state of balance. Aspring 12 is connected between the outer end of lever 3| and a clip 13secured to the cross channels for insuring the measuring rod being inposition against hitch plate during the weighing operation. To obviateany undue stress or breakage when the outer end of the lever 34 islocked, due for example to the inertia of the car during the stoppingoperation, the lever system is made flexible. This may be done forexample by providing a toggle joint 74 in lever 3| to permit downwardmovement of the inner end of this lever should the car move upwardlywith respect to the cross channels when lever 34 is locked in position.To form this toggle joint, lever 3| is made in two sections, onedesignated 15 and the other formed of two side members 16 and I!straddling the end of section 1.5. A stop plate 18 secured to the innerend of the side members 16 and I7 extends inwardly over the outer end ofsection 15. A stud 80 extends upwardly from the outer end of section 15through an aperture in the stop plate and a compression spring 8| isarranged on this stud between the stop plate and a washer secured to theend of the stud. This arrangement effectively transmits the movement oflever 3| to lever 34 but is yieldable to enable the toggle to be brokenupwardly in the event of upward movement of the car relative to thecross channels when lever 34 is locked. In case of relative movement ofthe car downward with respect to the cross channels when lever 34 islocked the hitch plate simply disengages the end of the rod.

When the car is empty the mechanism is in the position illustrated inFigure 3. As passengers enter the car, the car moves downwardly actingthrough plate |2 to compress the rubber pad. This causes upward movementof rod 26 relative to the car framework swinging lever 21 clockwiseabout its pivot. This causes counterclockwise movement of lever 3| whichin turn causes clockwise movement of lever 34 to move the inductorswitch downwardly relative to the car. When the car becomes fully loadedthe inductor switch and lever 34 assume the positions indicated indot-dash lines in Figure 3. The magnet 62 is energized to move the pawl65 into engagement with the rack 66 to lock lever 34 in position afterthe load weighing has been completed. Assuming that the car is movingupwardly, as it approaches a floor at which a stop is to be made, theinductor switch comes opposite the up inductor plate for that floor toopen the inductor switch contacts. The distance of the car from thefloor when this occurs is smaller the greater the load on the car owingto the fact that the greater the load the farther lever 34 has beenswung clockwise and therefore the closer the car will be to the floorwhen the inductor switch comes into cooperation with the plate. Shouldthe car have been started in the down direction, upon its approaching afloor at which a stop is to be made, the inductor switch comes oppositethe down inductor plate for that floor to open the inductor switchcontacts. The distance of the car from the floor when this occurs isgreater the greater the load on the car owing to the fact that thegreater the load the farther the lever 34 has been swung clockwise andtherefore the farther the car will be from the floor when the inductorswitch comes into cooperation with the plate. Thus the mechanism acts toeffectively compensate for the load on the car by varying the distancefrom the floor at which the stopping operation is initiated in such away as to cause the car to be brought to a stop at the landing. Inasmuchas the lever arm 34 is locked after the load is weighed, proper positionof the inductor switch with respect to the car for the stop initiatingoperation is assured. The lock magnet is deenergized to release theinductor switch after the stopping operation has been initiated so thatthe load may be reweighed for the next stopping operation.

Reference may now be had to Figure 6 which.

illustrates diagrammatically the control and power circuits of a pushbutton elevator system embodying the invention. The circuits are shownin straight or across-the-line form, in which the coils and contacts ofthe various switches are separated in such manner as to render thecircuits as simple and direct as possible. The relationship of thesecoils and contacts may be seen from Figure 6s wherein the switches arearranged in alphabetical order and shown in spindle form. The positionsof these coils and contacts in the wiring diagram may be found byreferring to Figure 6s, where the coils and contacts are positioned onthe spindles in horizontal alignment with the corresponding elements ofthe Wiring diagram.

The circuits for a four floor installation are illustrated. The carbuttons are designated CI, C2, C3 and C4 for the first, second, thirdand fourth fioors respectively. The car buttons act through fioor relaysdesignated IC, 20, 3C and 4C for the first, second, third and fourthfloors respectively. Where the first floor is the basement and thesecond floor is the main floor, both an up hall button and a down hallbutton are provided at the main floor in the particular control systemillustrated. Assuming that this is the case, these buttons are shown andare designated U2 and D2 for the up and down hall buttons respectively.These buttons respectively act through floor relays designated 2U and2D. Single hall buttons are provided at each of the other floors, thehall button at the first fioor (basement) being designated UI, the hallbutton at the third floor being designated D3 and the hall button at thefourth floor being designated D4. These hall buttons act respectivelythrough floor relays designated IU, 3D and 4D. Each of the floor relaysis of the latching type and has an operating coil and a reset coil, theoperating coils being in series with the respective push buttons and thereset coils being controlled by the selector.

The floor relays act in conjunction with direction determining mechanismon the selector to determine the direction of travel of the car. Thisdirection determining mechanism comprises a plurality of directorswitches designated I41, I42, I43 and I44 for the first, second, thirdand fourth floors respectively. The director switches are stationary andare spaced in accordance with the distance between the correspondingfloors. These switches are engaged by a direction cam arranged in threesections designated I45, I46 and I41, I45 being a down section, I45 aneutral insulated section, and I41 an up section. The floor relays alsoact to render the stationary contacts on the selector machine alive tobe engaged by brushes carried by the selector crosshead to pick up thecalls that are registered. These stationary contacts are arranged inthree columns. The stationary contacts in the first column aredesignated III, H2 and H3 for the first, second and third fioorsrespectively and are respectively controlled by floor relays IU, 2D and3D. The stationary contacts in the second column are designated I22 andI24 for the second and fourth floors respectively and are respectivelycontrolled by floor relays 2U and 4D. The stationary contacts in thethird column are designated I3I, I32, I33 and I34 for the first, second,third and fourth floors respectively and are respectively controlled byfloor relays IC, 2C, 30 and 4C. Stationary contacts I I I, H2 and I I3are engaged by down call pick up brush [I .and

reset brush H6, the reset brush engaging the stationary contacts whenthe car is stopped at the respective floors, while the call pick upbrush H5 is advanced ahead of the reset brush a distance greater thanstop initiating distance. Stationary contacts I22 and I24 are engaged byup call pick up brush I2! and reset brush I26, the reset brush engagingthe stationary contacts when the car is stopped at the respectivefloors, while the call pickup brush I21 is advanced ahead of the resetbrush a .distance greater than stop initiating distance. Stationarycontacts I3I, I32, I33 and I 34 are engaged by down call pick up brushI35, up call pick up brush I31 and 'reset brush I36, the reset brushengaging the stationary contacts when the car is stopped at therespective floors, while the call pick up brushes I35 and I3! areadvanced ahead of the reset brush in the corresponding directions of cartravel a distance greater than stop initiating distance.

The alternating current supply mains are designated I, II and III. SKindicates a triple pole knife switch controlling the connection of thepower mains to the system. The hoisting motor is illustrated as of thesquirrel cage induction type, the rotor being designated I50 and thestator windings I5I, I52 and I53. Resistances I54, I55 and I56 areconnected in series with the stator windings for controlling the torqueof the motor. The electromechanical brake is designated BR. EXAdesignates the armature, EXF the shunt field winding and EXS the seriesfield winding of an exciter for supplying certain of the controlcircuits. This exciter is driven by a polyphase alternating currentmotor, the rotor of which is designated I5! and the stator windings I58,I59 and I60.

While the hatchway doors in the system illustrated are manually openedand automatically closed, the car gate is power operated, for example bymechanism such as that schematically illustrated in the aforesaid Lewiset a1. Patent No. 2,101,146. I62 designates the rotor of the polyphasealternating current operating motor of such mechanism. The statorwindings of this motor are designated I63, I64 and IE5. GOL is a gateopen limit switch for controlling the operation of the gate operatingmotor. The gate contacts closed when the gate is closed are-designatedGS. The auxiliary door contacts closed when the hatchway doors areclosed are designated collectively ADS. The door interlock contactsclosed only when the respective hatchway doors are closed and locked aredesignated collectively DS. ES is the emergency stop switch in the car.Other safety devices are grouped and are indicated by the legendsafeties.

The electromagnetic switches employed in the system are designated asfollows:

Throughout the description which follows these letters will be appliedto the coils of the above designated switches. Also, with referencenumerals appended thereto, they will be applied to the contacts of theseswitches. Relay S is a latching relay having both an operating coil anda reset coil. The inductor electromagnet 54 has its coil designated INDin the wiring diagram with the numeral 54 added in brackets, whereas thecontacts 60 of the inductor are designated CX DL INDI in the wiringdiagram with the numeral 60 added in brackets. The electromagnet 62 ofthe locking device has its coil designated LM in the wiring diagram withthe numeral 62 added in brackets. The electromagnetic switches and theinductor switch are illustrated in deenergized condition while thelatching relays are illustrated in reset condition.

Assume that the car is standing idle at the second floor (main floor).The floor control circuits are illustrated in Figure 6 in accordancewith this assumption. As the car is idle, the second floor hatchway dooris closed but not locked and the car gate is open. Door lock contacts DSfor the second floor and gate contacts GS are therefore open. Theauxiliary door contacts ADS, however, ar closed.

Assume now that an intending passenger at the third floor presses hallbutton D3. This connects operating coil 3D of the corresponding floorrelay across two phases of the alternating current supply mains tooperate the floor relay. The floor relay is latched in operatedcondition permitting the push button to be released. The floor relayengages contacts 3DI, 3D2 and 3D3. The engagement of contact 3DIconnects the coil of exciter set starting switch ST across thealternating current supply lines causing this switch to operate. Uponoperation, relay ST engages contacts STI, STZ and ST3 to connect thestator windings of the exciter set driving motor to the alternatingcurrent supply mains, bringing the exciter set into operation.

As the exciter voltage rises to a certain value, door relay operates toengage contacts OI which completes the circuit for the coil of timerelay Z. Relay Z does not operate immediately contacts OI engage, beingdelayed as by a dash pot. Upon the expiration of this time intervalcontacts ZI and contacts Z2 engage. The engagement of contacts ZIcompletes the circuit for the coil of up reversing switch relay AU, thiscircuit being through interlock contacts EDI and B4, terminal stoppingswitch contacts I16, direction cam up section I41, third floor directorswitch hi3, floor relay contacts 3D3, resistance I13, and contacts ZI.Relay AU upon operation separates interlock contacts AUI to render downcall pick up brush II5 ineffective and separates interlock contacts AUZin the circuit for the coil of relay BD. It also engages contacts AU4 toprepare the circuit for the coils of up reversing switch A and potentialswitch C. It also engages contacts AU3 to complete a circuit for thecoil of reversing switch relay AB. Relay AB upon operation engagescontacts ABI by-passing time relay contacts ZI. It also engages contactsAB3 to complete a circuit through contacts SS2 for the operating coil ofcall pick up relay S. Relay S latches itself in operated condition,engaging contacts SI and contacts S3 and separating contacts S2.

Contacts SI of the call pick up relay complete a circuit for the coil ofgate relay DL and the coil LM of the locking device magnet throughcontacts AB3. The locking device acts to lock the load weighing devicein position. Under the assumed conditions, no one is in the car so thatthe inductor switch is locked in its uppermost position shown in fulllines in Figure 3. Relay DL engages contacts DLI and DL2 and separatescontacts DL3. The engagement of contacts DLI is without effect becausecontacts AB2 are separated. The engagement of contacts DL2 cornpletes acircuit for the coil of gate close switch GC. v

Gate close switch GC upon operation engages contacts GCI, G02 and GC3 tocomplete a circuit through portions of resistances Ill and I18 for thestator windings I63, I64 and IE5 of the gate operating motor for a phaserotation of the applied voltage to cause the closing of the car gate. Asthe gate starts to close, gate open limit switch GOL closes to completethe circuit for the coil of auxiliary exciter relay G, the circuit forthe coil of gate open switch GO being open at contacts DL3 and GC4.Relay G engages contacts G! in circuit for the coil of relay ST andseparates contacts G2 in circuit for the reset brushes IIS, I26 and I36of th selector. As the gate reaches closed position the retiring cam isretired to lock the second floor hatchway door and close the door lockcontacts DS thereof and the gate contacts GS close, completing a circuitfor the coils of potential switch 0 and up reversing switch A. Thiscircuit is through terminal stopping switch I8D, contacts AU4, S3 andINDI, door lock contacts DS, gate contacts GS and emergency stop switchES.

The up reversing switch upon operation engages contacts A5 to establisha self-holding circuit and separates interlock contacts A4 in circuitfor the coil of relay BD. Potential switch C upon operation engagescontacts CI and C2 which together with the engagement of contacts AI andA2 of the up reversing switch completes a circuit for the statorwindings I5I, I52 and I53 of the elevator hoisting motor for a phaserotation of the applied voltage to move the car in the up direction. Atthe same time'switch C engages contacts C3 and C4 and switch A engagescontacts A3 to complete a circuit for the brake release coil BR torelease the electro-mechanical brake and the car starts in the updirection. The brake in releasing opens brake switch BRI to insertcooling resistance I82 in circuit with the brake coil. Contacts A3 andC4 also complete a circuit for the coil of auxiliary potential switchrelay CX which operates to engage contacts OK I and OX2.

Contacts CXI by-pass contacts SI and AB3 in circuit for the coil of gaterelay DL. Contacts OX2 are in circuit for the coil of the inductorswitch IND, this circuit being now open at contacts S2. Contacts A3 andC4 also complete a circuit for the coil of accelerating switch K. SwitchK operates to engage contacts KI and K2 to short-circuit resistance I54,I55 and I 58 to apply full line potential to the stator windings of thehoisting motor, the operation of switch K bein delayed as by a dash pot.

Switch K also engages contacts K3 to complete the circuit for the coilof auxiliary time relay SS. Relay SS operates to engage contacts SSIestablishing a self-holding circuit. It also sepa rates contacts SS2 inthe circuit for the coil of call pick up relay S. Switch K alsoseparates contacts K4 which deenergizes time relay Z. Relay Z drops outto separate contacts Z2 which with the separation of contacts SS2deenergizes the operating coil of relay S. Relay S remains operated,however, since as previously pointed out it is latched in operatedcondition. Relay Z also separates contacts ZI3 this being withouteffect, however, as contacts ABI are engaged.

As the car approaches the third floor the upper section ll! of thedirection cam runs off the third floor director switch I43 which breaksthe circuit for the coil of up reversing switch relay AU. The resultantseparation of contacts AU4 is without effect as these contacts arelay-passed by contacts A5. The separation of contacts AU3 breaks thecircuit for the coil of auxiliary re versing switch relay AB. Relay ABdrops out to separate contacts AB3 but this is without effect as thecircuit for the operating coil of relay S is already broken at contactsZ2 and SS2 and as contacts CXI maintain the circuit for locking devicecoil LM and the coil of relay DL. AB also engages contacts AB2 whichcompletes a circuit through contacts DLI for the reset coil of call pickup relay S. This picks up the call for the third floor. The energizationof the reset coil of relay S causes this relay to be reset, resulting inthe separation of contacts SI, S3 and the engagement of contacts S2. Theseparation of contacts SI is without effect as these contacts arebypassed by contacts CXI. Also the separation of contacts S3 is withouteffect as these contacts are Icy-passed by contacts A5.

The reengagement of contacts S2 completes the circuit for the coil INDof the inductor switch through contacts 0X2. This renders the inductorswitch effective for cooperation with the up inductor plate in thehatchway for the third floor. As th inductor switch comes opposite thisplate it separates the inductor switch contacts INDI. Under the assumedconditions this occurs at maximum stopping distance for upward cartravel for the third floor owing to the fact that as the car is emptythe maximum amount of unbalanced weight of the counterweight acts as anoverhauling load to oppose the stopping operation. The separation of theinductor switch contacts breaks the circuit for the coils of upreversing switch A and potential switch C. The resultant separation ofcontacts CI, C2, AI and A2 breaks the circuit for the elevator hoistingmotor. The separation of contacts A3, C3 and C4 breaks the circuit forthe brake release coil to apply the brake thereby to slow down the carand bring it to a stop at the third floor.

The separation of contacts A3 and C4 also break the circuit for thecoils of auxiliary potential switch relay CX and accelerating switch K.Switch K in dropping out reengages contacts K4 to complete the circuitfor the coil of time relay Z. The time relay Z, as pointed out above, isdelayed in operating so that contacts 2! and Z2 remain separated.However, this does start the timing operation provided by relay Z. RelayOK in dropping out separates contacts CXI to break the circuit for coilLM of the locking device magnet while the separation of contacts OX2breaks the circuit for the coil IND of the inductor switch, these partshaving performed their function in the stopping operation. Theseparation of contacts CXI also breaks the circuit for the coil of gaterelay DL which in dropping out separates contacts DLI to deenergize thereset coil of relay S and separates contacts DLZ to deenergize the coilof gate close switch GC. The gate close switch in dropping out separatescontacts GCI, G02 and GC3 to deenergize the gate operating motor. Italso reengages contacts GC4 which together with the reengagement ofcontacts DL3 as a result of the dropping out of relay DL completes thecircuit for the coil of gate open switch GO.

Gate open switch GO upon operation engages contacts GOI, G02 and G03 tocomplete a circuit through other portions of resistances Ill and I18 forthe stator windings I63, I34 and I65 of the gate operating motor for aphase rotation of the applied voltage to cause the opening of the cargate. The gate open switch also separates contacts G04 to break thecircuit for the coil of time relay Z. This relay drops out imthat door.

mediately, cancelling the timing operation. As the gate starts to openthe retiring cam is extended to unlock the third floor hatchway door,causing the opening of door lock contacts DS for Also gate contacts GSopen. As the gate reaches open position, gate open limit switch GOLopens to deenergize the gate open switch G0 which drops out to separatecontacts GOI, G02 and G03, breaking the circuit for the gate operatingmotor. Also the opening of gate open limit switch GOL breaks the circuitfor the coil of auxiliary exciter relay G.

As the car comes into the floor the insulated section Hi6 of thedirection cam runs onto the third floor director switch I43 isolatingthe third floor direction and control circuits. Also the reset brushesmove into engagement with the third floor stationary contacts. Theengagement of contacts G2 as the result of the deenergization of relay Gestablishes a circuit through resistance I83, brush H3, stationarycontact H3 and floor relay contacts 3D2 for the reset coil of the thirdfloor relay 3D. This causes this relay to be reset. Also the separationof contacts GI and contacts 3DI breaks the circuit for the coil ofexciter set starting switch ST which drops out to separate contacts STI,STZ and 6T3. This breaks the circuit for the stator windings of theeXci-ter driving motor which shuts down the exciter set.

The door being unlocked the intended passenger may open the door andenter the car. Assume that he wishes to go to the first floor andpresses car button CI. This causes the operation of the correspondingfloor relay IC which is latched in operated condition, permitting thepush button to be released. The relay operates as previously describedfor floor relay 3D to start the exciter set in operation and as theexciter voltage rises to a certain value it causes the operation of theauxiliary reversing switch relay. In this case down relay ED isoperated, the circuit being through the coil of relay BD, contacts AUZand A4, terminal stopping switch contacts I15, direction cam downsection I45, second and first floor director switches I42 and IM andfloor relay contacts ICE. Relay BD engages contacts BD3 to cause theoperation of relay AB which in turn causes the operation of relay S.Relay S engages contacts SI which, assuming that the 'thid floor doorhas closed so that relay 0 is operated, completes a circuit for coil LMof the locking device magnet. This looks the weighing device in loadweighing position. In this position the lever 34 is swung slightlyclockwise from the position illustrated in full lines in Figure 3, as apassenger is in the car.

Relay DL upon operation causes the operation of gate close switch G0which in turn causes the closing of the car gate and the locking ofthird floor hatchway door. The resultant closing or the hatchway doorlock contacts completes a circuit for the coil of potential switch C andthe coil of down reversing switch B through contacts BD4. Switches B andC engage contacts CI, C2, C3, C4, BI, B2 and B3 to complete the circuitsfor the stator windings of the elevator hoisting motor and for the brakerelease coil to cause the starting of the car, the car being started inthe down direction owing to the fact that down reversing switch contactsBI and B2 establish a phase rotation of the voltage applied tothe statorwindings for down car travel. Contacts B3 and C4 also complete thecircuit for the coils of relay CX and switch K. Switch K acts to shortcircuit the resistance in circuit with the stator windings of thehoisting motor. It also completes the circuit for the coil of relay SSand breaks the circuit for the coil of time relay Z.

Assume that before the car arrives at call pick up distance from thesecond floor an intending passenger at that floor presses down buttonD2. This causes the operation of the corresponding floor relay 2D whichengages contacts 2D2 to render stationary contact H2 alive. Uponengagement of this contact by brush H5 a circuit is completed for thereset coil of call pick up relay S. This picks up the call for thesecond floor and resets the call pick up relay. The reengagement ofcontacts S2 completes the circuit for the coil IND of the inductorswitch. As the inductor switch comes opposite the down plate for thesecond floor, its contacts INDI are separated. Under the assumedconditions this occurs at a distance somewhat greater than minimumstopping distance for downward car travel for the second floor owing tothe fact that as a passenger is in the car, less than the fullunbalanced weight of the counterweight is being lifted so that slightlymore than this minimum stopping distance is required for the brake tostop the car. The separation of inductor switch contacts INDI breaks thecircuit for the coils of down reversing switch B and potential switch 0.These switches drop out to break the circuit for the elevator hoistingmotor and for the brake release coil and the brake is applied to slowdown the car and bring it to a stop at the second floor. Coil LM of thelocking device magnet and coil IND of the inductor switch aredeenergized by the separation of contacts CXI and OX2 respectively as aresult of the dropping out of the potential switch. Also the separationof contacts CXI causes the dropping out of relay DL and switch G0 whichreengage contacts DL3 and GC4 to complete the circuit for the coil ofgate open switch GO. Switch GO operates to cause the opening of the cargate and the unlocking of the second floor hatchway door. As the gatereaches open position gate open limit switch GOL opens to deenergizeswitch GO and relay G. Relay G engages contacts G2 to render brush H5efiective to cause the reset of floor relay 2D. The exciter set ismaintained in operated condition,

however, as contacts ICI of floor relay IC re- I main in engagement.

The engagement of contacts G04 as a result of the dropping out of switchGO as the gate reaches open position reestablishes the circuit for thecoil of time relay Z. This gives the intending passenger the intervalprovided by this relay in which to open the hatchway door and enter thecar. Should this not occur within this time interval, contacts Z2reengage to cause the relccking of the load weighing device in loadweighing position, reclosure of the car gate and locking of the secondfloor hatchway door and the restarting of the car in the down direction.Assume, however, that the passenger opens the door and enters the car.As he opens the door relays O and SS are deenergized, relay 0 cancellingthe time interval of relay Z. Upon the reclosure of the door relay 0reengages contacts OI which immediately completes a circuit for theoperating coil of call pick up relay S through contacts and. AB3 causingthe locking of the load weighing device in load weighing position andreclosure of the car gate and locking of the hatchway door andrestarting of the car in the down direction, without waiting for theexpiration of the time interval of relay Z. It is to be noted that asthere are now two passengers in the car lever 34 is swung furtherclockwise about its pivot from the position illustrated in Figure 3.

As the car nears the first floor, brush I35 engages contact 13! pickingup the call and resetting the call pick up relay. The consequentreengagement of contacts S2 renders the inductor effective forcooperation with the hatchway plate for the first floor. Thiscooperation takes place at a greater distance from the first floor thanwas the case with the previously assumed stop at the second floor owingto the fact that there are now two passengers in the car. The separationof inductor switch contacts INDl breaks the circuit for the coils ofswitches C and B causing the car to be brought to a stop at the firstfloor. Also the car gate is opened and the first floor hatchway door isunlocked. As the gate reaches open position relay G is deenergizedcausing the reset of first floor relay i0 and the exciter set is shutdown.

It is believed that it will be understood without further descriptionthat all push buttons, once pressed, are responded to, inasmuch as theyact through floor relays which are latched in operated position andremain so until the car stops at the corresponding floor in response tothe push button. The car buttons are responded to during travel of thecar in each direction, brush 13'! being effective to pick up car callsduring up travel and brush I35 during down car travel. Hall buttons D3and D2 are responded to during downward travel of the car, brush H5being effective to pick up these calls under such conditions. Duringupward travel of the car it may be stopped in response to hall button D3or hall button D2 provided no call is registered for a floor beyond tomaintain relay AU operated. However, the car on its upward trip may bestopped at the second floor in response to hall button 2U even thoughcalls are registered for floors above, brush E21 being effective to pickup this call. Contacts Zl prevent the immediate establishment of adirection circuit by a hall button floor relay upon the last stop of thecar in its direction of travel. For example, should the car on itsupward trip be stopped at the third floor in response to push button D3contacts 21 remain separated until the passenger has had time to openthe door and, after entering the car and reclosing the door, until thepassenger has had time to press the car button for his destination,thereby giving preference to car buttons for establishing direction ofcar travel under such conditions.

The locking magnet and inductor switch are deenergized each time a stopis made so that the load is reweighed for each stopping operation. Themore load that is on the car the more lever 34 is swung clockwise aboutits pivot, Figure 3. ihus the more load on the car the less the stopinitiating distance for stops during up car travel and the greater thestop initiating distance for stops during down car travel. Thuscompensation is provided for the load on the car to cause the car to bebrought to a stop at the floors.

It is to be understood that various changes may be made in theparticular arrangement shown and specifically described. For example,the construction of the locking mechanism may be varied and it may beused with other arrangements of load weighing mechanism. Although theinvention has been described as applied to a three phase alternatingcurrent installation, it is applicable to installation of other numbersof phases and also to direct current installations. A slow speedinstallation has been chosen to illustrate the invention and, althoughthe invention is particularly applicable to such installations, it isalso applicable to higher speed installations in which the load weighingmechanism may be employed to cause initiation of the slow down operationat various distances from the floor with the stopping operation effectedas another step. Also, although a control system has been described inwhich the car is controlled by push buttons which act to register callsand in which the calls remain registered until responded to, it is to beunderstood that the invention is applicable to other types of pushbutton systems such as single call push button systems and to systems inwhich operation of the car is controlled in other ways such as those inwhich the starting of the car is under the control of an attendant inthe car with slow down controlled by passengers and intending passengersthemselves or those in which the slow down and starting are under thecontrol of a car attendant, with the slow down initiated automaticallyafter movement of the control switch in the car to a certain position.

Thus it is apparent that many changes could be made in the arrangementand control of the load weighing mechanism and many apparently widelydiiferent embodiments of the inventioncould be made without departingfrom the scope thereof, and it is therefore intended that all mattercontained in the above description or shown in the accompanying drawingsshall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. An elevator installation in which an elevator car serving a pluralityof floors is provided with resilient means for supporting the load andin which lever mechanism is provided which is movable in accordance withthe deflection of said resilient means to weigh the load in the car andin which means is provided for initiating slow down of the car at adistance from a floor at which a stop is to be made determined by theposition of said lever mechanism, characterized in that means isprovided which is operable after the load has been weighed but beforethe car starts to hold said lever mechanism in the position to which itwas moved during the load weighing operations.

2. An elevator installation in which an elevator car serving a pluralityof floors is provided with resilient means for supporting the load andin which lever mechanism is provided which is movable in accordance withthe deflection of said resilient means to weigh the load in the car andin which means is provided for initiating slow down of the car at adistance from a floor at which a stop is to be made determined by theposition of the outer end of said lever mechanism, characterized in thatelectromagnetically operable means is provided for holding said outerend of said lever mechanism in load weighing position, and in that saidlever mechanism is yieldable to allow for any deflection of saidresilient means while said outer end of the lever is held.

3. An elevator installation in which an elevator car serving a pluralityof floors is provided with lever mechanism for amplifying at the outerend thereof the deflection of resilient means interposed in theconnection of the hoisting ropes to the car for weighing the load, andin which means is carried by said outer end of said lever mechanism andmovable thereby into positions for cooperation with stationary means inthe hatchway for said floors to initiate stopping of the car atdistancesfrom the fioors at which' stops are to be made determined by the load inthe car, characterized in that'an electromagnetically operated pawl isprovided for engaging a rack to lock said outer end of said levermechanism in load weighing position, and in that said lever mechanism isyieldable to allow for any defiection of said resilient means after saidouter end of the lever has been locked.

4. An elevator installation in which an elevator car serving a pluralityof floors is provided with lever mechanism for amplifying at the outerend thereof the deflection of resilient means interposed in theconnection of the hoisting ropes to the car for weighing the load, andin which means is carried by said outer end of said lever mechanism andmovable thereby into positions for cooperation with stationary means inthe hatchway for said floors to initiate stopping of the car atdistances from the floors at which stops are to be made determined bythe load in the car, characterized in that said resilient meanscomprises rubber arranged between the car frame and the hitch plate forthe hoisting ropes and having a plurality of holes to provide a certainratio of bulge area to eifective supporting area, with said effectivesupporting area greater than the square of the thickness.

5. An elevator installation in which an elevator car serving a pluralityof floors is provided with lever mechanism for amplifying at the outerend thereof the deflection of resilient means interposed in theconnection of the hoisting ropes to the car for weighing the load, andin which means is carried by said outer end of said lever mechanism forcooperation with stationary means in the hatchway for said floors toinitiate stopping of the car at distances from the floors at which stopsare to be made determined by the load in the car, characterized in thatsaid resilient means is a rubber pad, and in that means is provided forholding said lever mechanism in load weighing position.

6. An elevator installation in which an elevator car serving a pluralityof floors is provided with lever mechanism for amplifying at the outerend thereof the deflection of resilient means interposed in theconnection of the hoisting ropes to the car for weighing the load, andin which means is carried by said outer end of said lever mechanism forcooperation with stationary means in the hatchway for said floors toinitiate stopping of the car at distances from the floors at which stopsare to be made determined by the load in the car, characterized in thatsaid resilient means is a rubber pad arranged between a hitch plate towhich the hoisting ropes are connected and the car framework, in thatthe cooperating means carried by said lever mechanism comprises aninductor switch, with inductor plates as the stationary means, and inthat means is provided for latching said lever mechanism in loadweighing position.

'7. An elevator installation in which an elevator car serving aplurality of floors is provided with lever mechanism. for amplifying thedeflection of resilient means interposed in the connection of thehoisting ropes to the car for weighing the load. and in which means ismovable by said lever mechanism into position for cooperation withstationary means in the hatchway for said floors to initiate stopping ofthe car at distances from the floors at which stops are to be madedete'- mined by the load in the car, characterized in that saidresilient means is a rubber pad arranged between a hitch plate to whichthe hoisting ropes are connected and the car framework and that saidlever mechanism comprises an inner lever and an outer lever bothpivotally mounted on said car framework with the inner end of said innerlever provided with means associated with said hitch plate to measurethe compression of said pad by the load in the car, in that thecooperating means movable by said lever mechanism comprises an inductorswitch carried by the outer end of the outer lever, with inductor platesas the stationary means, and in that means is provided for locking saidouter lever in load weighing position.

8. An elevator installation in which an elevator car serving a pluralityof floors carries means for cooperating with stationary means in thehatchway for the floors to initiate stopping of the car at said floors,and in which the cooperating means carried by the car is movable bylever mechanism, connected to amplify the deflection of resilient meansinterposed in the connection of the hoisting ropes to the car forweighing the load, into positions for cooperation with said stationarymeans at distances from the floors at which stops are to be madedetermined by the load in the car, characterized in that said resilientmeans is a rubber pad arranged between a hitch plate to which thehoisting ropes are connected and the car framework and that said levermechanism comprises an inner lever and an outer lever both pivotallymounted on said car framework with the inner end of said inner leverprovided with means associated with said hitch plate to measure thecompression of said pad by the load in the car, in that the cooperatingmeans carried by the car comprises an inductor switch carried by theouter end of the outer lever, with inductor plates as the stationarymeans, in that means is provided for locking said outer lever in loadweighing=position, and in that said lever mechanism is yieldable toallow for movement of said rod with respect to said outer lever due torelative movement between said car framework and hitch plate after saidouter lever has been locked.

9. An elevator installation in which an elevator car serving a pluralityof floors carries means for cooperating with stationary means in thehatchway for the floors to initiate stopping of the car .s

means is a rubber pad arranged between a hitch plate to which thehoisting ropes are connected and the car framework, in that a downwardlyextending measuring rod rests on said hitch plate to measure thecompression of said pad by the load in the car, said lever mechanismcomprising an inner lever and an outer lever both pivotally mounted onsaid car framework with the inner end of said inner lever connected tosaid rod. in that the cooperating means carried by the car comprises aninductor switch carried by the outer end of the outer lever, withinductor plates as the stationary means, in that an electromagneticallyoperated pawl is provided for engaging a rack to lock said outer leverin load weighing position, in that said inner lever has a toggle joi tyieldable to allow for movement of said rod with respect to said outerlever due to relative movement between said car framework and hitchplate after said outer lever has been locked.

it. An elevator installation in which an elevator car serving aplurality of floors carries means for cooperating with stationary meansin the hatchway for the floors to initiate stopping of the car at saidfloors, and in which the cooperating means carried by the car is movableby lever mechanism, connected to amplify the deflection of resilientmeans interposed in the connection of the hoisting ropes to the car forweighing the load, into positions for cooperation with said stationarymeans at distances from the floors at which stops are to be madedetermined by the load in the car, characterized in that said resilientmeans is a rubber pad arranged between a hitch plate to which thehoisting ropes are connected and an upper plate beneath the upper crossmembers of the car framework, in that a m asuring rod extends downwardlythrough aperture provided in said upper plate and pad to rest on saidhitch plate to measure the compression of said pad by the load in thecar, said lever mechanism being connected to said rod and comprising aninner lever and an outer lever both pivotally mounted on said crossmembers with the inner end of inner lever connected to said rod, in thata spring acting through the inner lever is provided to bias saidmeasuring rod into engagement with said hitch plate, in that thecooperating means carried by the car comprises an inductor switchcarried by the outer end of the outer lever, with inductor plates as thestationary means, in that a rack is mounted on the outer lever adjacentth switch and an electromagneticall operated pawl is mounted on saidcross inem. ers for en aging said rack to lock said outer lever in loadweighing position before the car is started, and in that said inner everhas a toggle joint yieldab-le to allow for movement of said rod withrespect to said outer lever clue to relative movement between said carframework and hitch plate after said outer lever has been locked.

SELDEN BRADLEY SANFORD.

